ADSORPTION-KINETICS OF END-ATTACHING TRIBLOCK COPOLYMERS

Ellipsometry is used to obtain the first measurements of the adsorption kinetics and adsorption isotherm of a doubly end-attaching polymer. A triblock copolymer of poly(ethylene oxide)-polystyrene-poly(ethylene oxide) is adsorbed onto silicon dioxide from toluene; only the polar-end blocks adsorb. At short times, the kinetics of adsorption follow Fickian behaviour. At small bulk concentrations, the surface saturation is approached monotonically but as the bulk concentration is increased an 'overshoot' in the adsorbed amount is observed. The adsorbed amount of triblock copolymer is less than the amount found for a corresponding diblock copolymer. This difference is attributed to the presence of triblock copolymers adsorbed in a loop-like conformation.